In construction, there is a need to tether construction workers to the structure being constructed, so that if the worker falls, the fall is short rather than deadly. What are known as “anchor points” have been provided in the prior art to help serve this purpose. Anchor points attach to the structure, e.g., the floor, wall, roof, or other structural element, and typically have a ring or through-hole to which a lanyard, strap or cable can be attached. That part of the anchor point that mounts to the structure can vary considerably; however, anchor points having rings generally share the characteristic that the ring is either fixedly disposed, or if it pivots, it does so such that the plane of the ring sweeps through a range of angles (e.g., 0-180 degrees) relative to the plane defining the surface to which the anchor point is mounted.
FIG. 1 illustrates the described pivoting. An anchor point 2 comprises a ring 4 and a strap 5 which mounts the ring to a structure 8 defining a mounting surface 6. A Cartesian coordinate system is also shown for reference. The x and y axes of the coordinate system are aligned with the mounting surface 6. The ring defines a plane “P” that pivots about a line “A” which is aligned with the x-axis. A line “B” is chosen that both lies in the plane P and is perpendicular to the line A, and the ring can pivot such that the angle δ defined between the line B and the mounting surface 6 varies between 0 and 180 degrees. Such anchor points will be referred to herein as pivot anchor points.
The pivot anchor point allows for pivoting that tracks a worker's movements in a plane aligned with the y and z axes. However, the present inventor has recognized that there is a need for an anchor point that provides for pivoting about the z axis, to track the worker's movements in a plane aligned with the x and y axes.